1. Field of the Invention
The present invention relates to machining systems and, in particular, to a machining system that can efficiently ensure the safety of an operator in a machining system formed of elements including a machine tool and a robot.
2. Description of the Related Art
In the past, in a machining system in which a robot and a machine tool are included as component elements, in order to establish a machining system having high productivity, the operation speed of the robot, the door opening and closing speed and the shaft feed speed of the machine tool, and so forth have been increased based on the premise that an operator does not enter the system. However, in recent years, the development of “a robot that does not require a safety fence” which makes it possible for an operator to perform operation such as replacement of a pallet and replenishment of workpiece without stopping the operation of a robot has been advanced.
These robots use a sensor and the operations thereof are restricted depending on the distance between the operator and the robots. If these robots are applied to a robot system, since the operator also gains access to the machine tool provided in the same machining system, as described in Japanese Patent Application Laid-Open No. 2003-107170 and Japanese Patent Application Laid-Open No. 2002-054791, for example, it is necessary to add another sensor for use in restricting the operation of the machine tool.
Moreover, the technique of making it possible to perform safe and efficient operations even in an environment in which a robot and an operator are close to each other by making it possible to change at any time the operation range of the robot and the forbidden area for the operator by using a sensor and a safety controller is disclosed in Japanese Patent Application Laid-Open No. 2007-283450. Furthermore, the technique of restricting the operation range of a robot by setting the operation area of an operator by attaching a receiver to the robot and a transmitter to the operator and detecting the position of the operator with respect to the robot based on the information obtained by the receiver and the transmitter is disclosed in Japanese Patent Application Laid-Open No. 2006-043862.
However, in order to introduce the techniques disclosed in the above-described patent documents, it is necessary to install a sensor for an operation restricting sensor for each of the robot and the machine tool in order to ensure the safety of the operator, which poses a problem in terms of costs. On the other hand, if the operation speed of the machine tool is increased, giving weight to efficiency as in the existing techniques, without installation of a sensor, attaching importance to costs, when the operator performs operations such as replacement of a pallet and replenishment of workpiece or erroneously enters an area near the machine tool, the operator may be exposed to danger, for example, chips, a workpiece not fixed in an adequate manner, or the like are thrown out of the machine tool when the door is opened and closed or a table, a column, or a spindle operates at high speed. However, if the operation of the machine tool is restricted in order to ensure the safety of the operator, the operation is restricted even when the operator is not present, which reduces efficiency.